Swift闭包-如何传递参数且没有返回值

Question

In the following code, I'm trying to create a closure that is passed a single parameter that will be used in the closure, where no value is returned:

The code is called from another Swift class in my app via runit()

Cannot invoke value of type '(CheckerOperation) -> ()' with argument list '(CheckerOperation)' at the line “runTimerProcess(runitProcess(customOperation))

I don't understand how to invoke when the closure will not be returning a value.

( CheckerOperation is just a custom NSOperation class)

class Checker {
  var queue = NSOperationQueue()
  let customOperation : CheckerOperation = CheckerOperation()

  var runitProcess: (CheckerOperation) -> () = {op in
        NSOperationQueue.mainQueue().addOperationWithBlock({
        let operationQueue = NSOperationQueue.mainQueue()
        operationQueue.addOperation(op)
    })
  }

  func runTimerProcess(closureblock: ClosureBlock){
    let queue = dispatch_queue_create(“myqueue”, DISPATCH_QUEUE_SERIAL)
    dispatch_async(queue,closureblock)
  }

  func runit(){
     runTimerProcess(runitProcess(customOperation))
  }
}

Answer 1

You're mixing two core syntaxes: (1) computed properties , and (2) functions/methods .

Computed properties cannot accept arguments. For your case, you should be simply defining a function with an argument op with a type of CheckerOperation . I say this because you don't appear to need to return or check a value on runitProcess which is really what a computed property is intended for.

Use this:

func runitProcess(op: CheckerOperation) {
    NSOperationQueue.mainQueue().addOperationWithBlock({
        let operationQueue = NSOperationQueue.mainQueue()
        operationQueue.addOperation(op)
}